package com.example.filter;

import com.alibaba.fastjson2.JSON;
import com.example.pojo.Result;
import com.example.utils.JwtUtils;
import jakarta.servlet.*;
import jakarta.servlet.annotation.WebFilter;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.StringUtils;

import java.io.IOException;

@Slf4j
//@WebFilter(urlPatterns = "/*")
public class LoginCheckFilter implements Filter {

    //request 请求参数
    //response 响应结果
    //chain 放行操作
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse res = (HttpServletResponse) response;

        //1.获取请求url
        String url = req.getRequestURI();
        log.info("请求url: {}", url);

        //2.判断请求url中是否包含login, 如果包含, 说明是登陆操作, 放行
        if (url.contains("/login")) {
            log.info("登陆操作");
            chain.doFilter(request, response);
            return;
        }

        //3.获取请求头中的令牌(token)
        String jwt = req.getHeader("token");

        //4.判断令牌是否存在, 如果不存在, 返回错误结果(未登录)
        if (!StringUtils.hasLength(jwt)) {
            log.info("请求头token为空, 返回未登录的信息");
            Result error = Result.error("NOT_LOGIN");
            //手动转换 对象-->json
            String notLogin = JSON.toJSONString(error);
            res.getWriter().write(notLogin);
            return;
        }

        //5.解析token, 如果解析失败, 返回错误结果(未登录)
        try {
            JwtUtils.parseJWT(jwt);
        } catch (Exception e) {//jwt解析失败
            e.printStackTrace();
            log.info("解析令牌失败, 返回未登录错误信息");
            Result error = Result.error("NOT_LOGIN");
            //手动转换 对象-->json
            String notLogin = JSON.toJSONString(error);
            res.getWriter().write(notLogin);
            return;
        }

        //6.放行
        log.info("令牌合法, 放行");
        chain.doFilter(request, response);
    }

}
